.header{
    height: 60px;
    position: sticky;
    z-index:999;
}
.header ul{
    height: 60px;
    position: fixed;
    top: 0;
    left: 0;
    border-bottom: 1px solid #f1f0f0;

    background-color: #ffffff;
}
.header ul li:nth-child(1){
    float:left;
}
.header ul li:nth-child(2){
    float:left;
}
.header ul li:nth-child(3){
    float:right;
}
.logo{
    height:60px;
    line-height: 60px;
}
.logo img{
    height:50px;
}
.login{
    height:60px;
    line-height: 60px;
}